Average Line return incorrect value when in calculation grouo exists calculations like MOM, two SELELECTEDMEASURE, for example
SELECTEDMEASURE ()- CALCULATE ( SELECTEDMEASURE (), SAMEPERIODLASTYEAR ( 'financials'[Date] ) )
is very easy make the error condition, using excel include in power bi (Financial),
1- make one simple measure
2- make one calculation groups with calc of style MOM o MOM %
remove calculation group item, and average line work fine
this problem not occurs with others analytics lines
it is by design.
Calculation groups are not compatible with implicit measures.
It is described in the documentation, too:
When you enable calculation groups, Tabular Editor enables the Model option Discourage Implicit Measure.
If you remove all the calculation groups, you can restore that property to False to enable implicit measures again.
and also see more details in this post: